Reactive materials

ABSTRACT

The invention relates to high density reactive materials, preferably materials with a high density and exothermic output 
     There is provided a high density reactive material comprising,
         A) at least two separate group 4 metals, present in the range of from 40 to 90% wt   B) at least one oxidiser or alloying metal, present in the range of from 5 to 55% wt   C) a binder present in the range of 1-10% wt.
 
wherein said reagents and optional pressing aids are present in substantially 100% wt.

The invention relates to high density reactive materials, preferably materials with a high density and exothermic output.

High Density reactive materials (HDRM) are a new emerging class of materials http://en.wikipedia.org/wiki/Reactive_materials, which have higher densities than conventional reactive materials such that they may provide enhanced performance with mechanical properties suitable for application in a broad range of weapon systems. This includes potential for effective transfer of Kinetic Energy in impact penetrators, fragments and other systems, whilst offering an additional advantage of providing a further exothermic output under explosive loading or following High Velocity impact.

According to a first aspect of the invention there is provided a high density reactive material composition comprising,

-   -   A) at least two separate group 4 metals, present in the range of         from 40 to 90% wt     -   B) at least one oxidiser or alloying element, present in the         range of from 5 to 55% wt     -   C) a binder present in the range of 1-10% wt.         wherein said reagents A), B), C) and optional pressing aids are         present in substantially 100% wt.

Preferably B) is at least one oxidiser. The at least one oxidiser may preferably present in the range of from 35 to 55% wt.

The at least one oxidiser may be a metal salt, such as, for example, oxides, nitrates, perchlorates, permanganates, peroxides, chlorates. Preferably a high density metal salt, such as for example, metal oxides, for example CuO.

The reagent B) when selected from an alloying element may be selected from any non-group 4 metal, metalloid, that undergoes an exothermic alloying reaction with group 4 metals, preferably carbon or boron. The boron may be present in an amount 5 to 20% wt, preferably 10% wt.

The reagent A) group 4 metals are group 4, d-block (transition metals) such as titanium, zirconium, and hafnium. These metals offer high densities, and the specific selection of two different group 4 options offers a chance to target specific density ranges for the final composition whilst retaining similar reactivity.

In a preferred arrangement at least one of the group 4 metals is hafnium. Preferably the hafnium is present in the range of from 15 to 30% wt. The specific inclusion of Hafnium, in the range of from 15 to 30% wt, or more preferably in the range of 20 to 25% wt, which provides a significant increase to the overall effective density of the consolidated composition, for a relatively minor volumetric inclusion.

The group 4 metals may offer a range of morphologies—comprising nano, sub micron, or micron sized particulates. The at least two group 4 metals may be selected to maximise mixing capability to promote uniformity of distribution (these may be substantially the same size, or targeted different size ranges to achieve a specific multimodal distribution, such as a bimodal distribution.

The reagent B may be selected from nano, sub micron, or micron sized particulates, such that upon intimate mixing with group 4 metals, may support/provide a homogenous mixture. The particulate size of the group 4 metals and reagent B materials may be selected to provide multimodal distributions.

The reagent C) binder may be selected from at least one fluoroelastomer binder. The fluoroelastomer binder may be selected from a range of materials such as for example hexafluoropropylene, vinylidene fluoride, terpolymers of tetrafluoroethylene, vinylidene fluoride and hexafluoropropylene (HFP), perfluoromethylvinylether, THV 220, and PTFE, preferably a Viton, more preferably Viton A.

The reagent C) binder may preferably be present in the in the range of from 3 to 7% wt, preferably 5% wt.

According to a further aspect there is provided a munition comprising a portion of the consolidated composition as defined herein. The portion of the munition may comprise all, substantially all or part of a munition. The munition may such as for example be a direct fire or indirect fire munition. The munition may be kinetic energy or chemical energy munition or a combination thereof, such as, for example a projectile, shell, casing, shaped charge liner, preformed fragments or mortar.

The munition may be a kinetic energy projectile such as for example, such as a round, from a small calibre ordnance, a medium calibre projectile such as, for example calibres of 30-40 mm and above, penetrator rods or flechettes. The projectile may comprise or contain only a monolithic projectile of consolidated composition as defined herein. Certain medium calibre projectiles typically comprise a high explosive, the use of a projectile (small or medium calibre) comprising or containing only a consolidated composition according to the invention may provide an insensitive munition.

The munition may be a gun launched shell, such as for example, 105 mm or 155 mm, wherein part, substantially all or all of the shell casing is a composition as defined herein. The composition may be prepared to form pre formed fragments which are further consolidated to form a shell casing. In a munition subjected to a high set back force, such as a gun launched munition, preferably there is a higher percentage weight of fluorelastomer binder.

The munition may comprise at least one layer deposed thereon of the composition as defined herein.

The casing of the munition may be subjected to prompt break up, ignition and burn to enhance blast effectiveness.

The particulates of the composition may not be consolidated and may be available as agglomerates/clumps, and may be ignited as such, and undergo ignition and continue to burn in flight. This may offer enhancement to blast and after burn or Kinetic Energy transfer to targets at range.

The composition either solid or agglomerates may be ejected, or projected, in such a manner to retain physical form/mass and associated Kinetic Energy allowing reaction on impact with targets at a specific thresh-hold impact velocity causing shock reaction and ignition of the material on the surface or within the target structure.

According to a yet further aspect of the invention there is provided a method of preparing a high density reactive material as defined herein, such as for example, dead load pressing, isostatic pressing, hot sintering, to provide a composition which may be consolidated to form a structural casing or projectile.

TABLE 1 Overall Effective Ingredient 1 Ingredient 2 Ingredient 3 Ingredient 4 Density by Ref Name Wt % Name Wt % Name Wt % Name Wt % Wt fraction 1a Zirconium 25% CuO 50% Viton A 5% Hafnium 20% 6.27 21a Titanium 35% Boron 10% Viton A 5% Hafnium 50% 5.46 23a Hafnium 51% Boron 10% Viton A 5% Zirconium 34% 6.28 25a Titanium 25% CuO 45% Viton A 5% Hafnium 25% 5.79 26a Hafnium 20% CuO 45% Viton A 5% Zirconium 30% 6.28 28a Zirconium 45% THV220 10% Tungsten 45% 5.71 29a Hafnium 79% THV220 10% Zirconium 11% 6.29 U1 Zirconium 45% Zinc 40% Tungsten 15% 7.53

-   -   Table 1 provides a number of examples where the composition         comprises a group 4 metal present in the range of from 45 to 95%         wt. the materials are sintered, preferably using both elevated         temperatures and pressure with the a binder and optional         pressing aids to facilitate consolidation.

TABLE 2 Overall Effective Reagent A Reagent B Reagent C Reagent A Density by Ref Name Wt % Name Wt % Name Wt % Name Wt % Wt fraction 1a Zirconium 25% CuO 50% Viton A 5% Hafnium 20% 6.27 21a Titanum 35% Boron 10% Viton A 5% Hafnium 50% 5.46 23a Hafnium 51% Boron 10% Viton A 5% Zirconium 34% 6.28 25a Titanium 25% CuO 45% Viton A 5% Hafnium 25% 5.79 26a Hafnium 20% CuO 45% Viton A 5% Zirconium 30% 6.28

-   -   Table 2 above, provides preferred examples of compositions,         wherein at least two different group 4 metals are selected.

The group 4 metals may be encapsulated or a passivation layer, or sacrificial layer to prevent reaction with air, moisture or unwanted reactions with the other reagents, until activated in the designed mode of use. The group 4 metals may be encapsulated with at least one inert material, to prevent reaction with moisture or air. Preferably by premixing the group 4 metal with reagent C) a binder, preferably a fluoroelastomer. The coating/microencapsulation of the group 4 metal may prevent combustion in air during the sintering process.

According to a further aspect of the invention there is provided a high density reactive material composition comprising,

at least one group 4 metal, present in the range of from 45 to 90% wt at least one oxidiser or alloying element, present in the range of from 5 to 55% wt a binder present in the range of 1-10% wt. wherein said reagents and optional pressing aids are present in substantially 100% wt, wherein said consolidated composition provides an effective density by weight fraction of greater than 5.40. 

1. A high density reactive material composition, comprising: A) at least two separate group 4 metals, present in the range of from 40 to 90% wt; B) at least one oxidiser or alloying element, present in the range of from 5 to 55% wt; and C) a binder present in the range of 1-10% wt; wherein said reagents and optional pressing aids are present in substantially 100% wt.
 2. The composition according to claim 1, wherein B) is at least one oxidiser.
 3. The composition according to claim 1, wherein the at least one oxidiser is a metal salt.
 4. The composition according to claim 1, wherein the at least one oxidiser is present in the range of from 35 to 55%.
 5. The composition according to claim 1, wherein at least one of the group 4 metals is hafnium.
 6. The composition according to claim 5, wherein the hafnium is present in the range of from 15 to 30% wt.
 7. The composition according to claim 1, wherein said binder is a fluoroelastomer binder.
 8. The composition according to claim 7, wherein said fluoroelastomer binder is present in the range of from 3 to 7% wt.
 9. The composition according to claim 1, wherein the at least two group 4 metals are encapsulated.
 10. A munition comprising the composition according to claim
 1. 11. The munition according to claim 10, wherein the composition comprises all, substantially all, or part of a projectile, a shell, a casing, a shaped charge liner, one or more preformed fragments, or a mortar.
 12. A high density reactive material composition comprising, at least one group 4 metal, present in the range of from 45 to 90% wt. at least one oxidiser or alloying element, present in the range of from 5 to 55% wt; and a binder present in the range of 1-10% wt; wherein said reagents and optional pressing aids are present in substantially 100% wt, and wherein said composition provides an effective density by weight fraction of greater than 5.40.
 13. (canceled)
 14. The composition according to claim 12, wherein the at least one oxidiser or alloying element is a metal salt present in the range of from 35 to 55%.
 15. The composition according to claim 12, wherein the at least one group 4 metal is hafnium.
 16. The composition according to claim 15, wherein the hafnium is present in the range of from 15 to 30% wt.
 17. The composition according to claim 12, wherein said binder is a fluoroelastomer binder present in the range of from 3 to 7% wt.
 18. The composition according to claim 12, wherein the at least one group 4 metal is encapsulated.
 19. A munition comprising the composition according to claim
 12. 20. The munition according to claim 19, wherein the composition comprises all, substantially all, or part of a projectile, a shell, a casing, a shaped charge liner, one or more preformed fragments, or a mortar.
 21. A munition casing, comprising the composition according to claim 12, wherein the composition is formed into a plurality of preformed fragments consolidated to form the munition casing. 